Machines for crosscutting paper or cardboard webs have as is known two rotatably mounted blade drums mounted one above the other in a machine frame and having blades that cut through a material web passing through between them. The machine frame is comprised of side walls that are connected to each other by means of crosswise traverses. In the known crosscutting machines the machine frame is constructed of welded steel. The traverses are welded to the side walls. Normally the side walls are made of several side parts that are screwed or welded together. Such a construction is seen in German 198 03 522.